About supercurio

In current Voodoo Screen Tests Patterns app, that allows to measure displays of Android devices, I draw a OvalShape that has a background color following a specific sequence expected by a software controlling a colorimeter.

However as Erica Griffin noticed, on some devices the near-black measurements were inconsistent with what you could perceive with your own eyes or by taking pictures or filming the display using long exposure times.
Additionally, in my measurements I was most of the time getting readings for black on LCD panels (a fair amount of blue leaking, some red and green) while measuring the same thing on IRE1 (RGB 3, 3, 3), IRE2 (RGB 5, 5, 5) and then having a valid reading for IRE 3 (RGB 8, 8, 8).

There was then something wrong with my app designed to help running accurate display measurements, FAIL!

Long story short, the bug was not in my app but in Android graphic framework, but only on some devices and not the ones I used and tested during development.

Unfortunately he also released a working exploit with complete source code before the various vendors affected (Samsung, Meizu and surely others) were made aware of it, leading to a severe security issue without accessible fix for now.

I wrote then an application to circumvent the issue while manufacturer patch the security hole and publish OTA updates.

However, please note its a partial fix that cannot secure completely your device which is to date impossible without modifying it − an operation that will stop the ability to install OTAs without an external tool.

That’s why I would still recommend to consider Chainfire’s solution linked below.

Cannot protect efficiently against some potential attacks (typically, on boot).
The real fix by manufacturers or some carefully written custom kernels will indeed be the only true solutions to this vulnerability − and won’t introduce any feature regression like this one does with some firmwares on cameras.

Add missing Internet permissions for Flurry analytics:
I will likely share installation figures with my Samsung security contacts, so they get an idea of the interest generated by this kind of early fix.

Release of Archos GamePad tablet based on a RockChip dual core 1.6 GHz SoC with 4-core Mali 400 MP made me curious about this kind of hardware.

Archos tablet is announced at a price point of 149€ with Jelly Bean, 8GB of total storage and an interesting physical button mapping tool.Thanks to Jean Luc Castellani, JBmm.fr author, I had a glimpses of what’s inside this one after he sent me a Voodoo Report.

Yesterday I saw something similar but priced at 99.99€ instead as I was running errands in a French Leclerc general store: the DEA Factory MyPlay

99.99€, possibility to return it during 7 days (no re-stocking fee). Sold!

Honestly I was first surprised it was working properly as I was expecting much worse for such a cheap price. So I was quite impressed by the fact it’s a complete device.
I won’t make a full review here but just observations, de-facto incomplete.

Things I liked:

Working and configurable HDMI output

Okay headphone audio quality: not outstanding but surprisingly better than many pricier devices on market.

Audio measurements:

Like I said audio is quite decent when you plug headphones. The audio codec is not named by its driver so I don’t know exactly what’s inside.

THD values are low, and IMD+Noise stay reasonable as well unless you increase the output volume which leads to no obvious distortion but still an audible loss in quality when driving high quality low distortion headphones like Sennheiser HD 650.

Jitter is present but typically not audible, there’s no resampling artifacts either and frequency response is quite flat. If I bought this device it was also to measure how an Android device made of as cheap as it gets components was doing in the audio department and once again I’m observing price is not an indicator of audio quality.

Hiss, tested with very sensitive isolating Sennheiser SE535 in-ears is audible but okay. With some ALSA hacking the amp becomes almost black with no audible noise. Once again this is something many device sold at much higher price are unable to do.

Maximum volume is also quite loud (sorry no measurements here) and I doubt you’ll be lacking here with any kind of headphones.

Some context

Also, compared to previous HD displays using the same tech, it doesn’t suffer from visible grain or texture anymore when displaying non-bright pixels, and the luminance is also a lot more homogeneous which indicates new methods are used during its fabrication.

Super AMOLED color rendering accuracy and consistency across multiple samples always has been a huge difficulty for Samsung because of weak factory calibration process and possibly unstable materials.
I’ve been delight noticing with Galaxy S III, a lot of great work has been done by their engineers on this: consistency between devices seems improved (I’ll need more data here to really talk about that) and factory calibration seems good.

If the “panels” engineers did huge progress this time, there’s still a lot to critic about what have been done probably by another team, who turned every knobs like

Display sharpness

Color saturation

Response curve in shadows

…to the red zone, when, you know, it becomes “too much”.

Measurements

So.. where should we look at in those graphs?

First, there’s an issue with shadows, it should be noticeable in the luminance graph right?But.. nope, it’s not visible this way. Let’s switch to another view with the gamma graph:Issue spotted! Lets investigate a little more with near black measurements:Leaving no doubt, the color profile attached to the display is mis-configured in its shadow part: the curves should follow the dotted one.

The answer

Galaxy S III (let me precise one more time: GT-I9300 version) is indeed not calibrated properly. US Galaxy S III have are calibrated differently.
There’s no real point saying its hardware or software related because it’s a driver mis-configuration. So the result is about the same. I mean: some display hardware with issues could be corrected by applying a color profile calibration.

However let’s be clear: there’s should be nothing wrong with the hardware except if you got unlucky and in this case I recommend an exchange.

The issue is fixed in Display Expert prototype, and it has no side effect whatsoever.
So.. you’ll see more about that later.